Today's motor controllers--e.g. DC drives, servo controllers and frequency converters--are digitally controlled, with a huge number of control possibilities made possible through the digitization. Most electronic control devices are programmed via a menu consisting of a number of parameters to be set. For example, setting a Danfoss (manufactured by Danfoss A/S, Nordborg, Denmark) frequency converter VLT.RTM. series 3000 to ramp up the motor in 45 seconds requires programming of parameter number 217 to "45". However, this means some maneuvering on the user panel located on front of the unit. First step is selecting the right group, which can be found by looking in the user manual. After selecting Group 2 "Operations set up", next the correct parameter number for "Ramp up" must be located. Again, the user manual will help. The correct parameter number is 217, which can then be set to "45". During this single programming step the buttons on the user panel have been activated quite a few times, and consulting the user manual was necessary.
For the optimal setting of a frequency converter a minimum of about 10 parameters have to be accessed and set up, which is cumbersome and time consuming from the front panel on the unit. However, linking the motor controller to a personal computer (PC) and programming, monitoring or servicing the motor controller with the software on the PC is another way of accessing the motor controller. U.S. Pat. No. 5,392,207 to Wilson et al. describes a motor controller connected to a PC which incorporates software for servicing the motor controller. Wilson improves the user interface between operator and motor controller during troubleshooting by creating on the PC monitor a sequential flow diagram consisting of boxes, where the flow diagram is a graphical representation of the program to be run by the motor controller. It is then possible to run through the program for the motor controller step by step and to follow the movements on the flow diagram, thereby checking that the sequence is correct. However, Wilson does not deal with the user interface at the initial set up of the motor controller.
The user interface is typically a hand held terminal with a screen display or a personal computer, which is more comfortable because of the larger view. The huge number of parameters which can be set up on the frequency converter - in some cases more than 200 combined with the many options added to the software interface tend to confuse the operator. Not only has he to memorize the parameter numbers or use time to seek information about them, he is also confronted on the screen with an abundance of information and programming choices to be made.